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APPENDIX                                     237

The ethers are also formed by the action of sodium alcoliolatc
on the alkyl iodide (Williamson),
C,ll;,()Nu -|  C,IIr,T = C,Ha.O.C2IIs -I- Nal,
and by this method mixed ethers may also be prepared.
The inertness of the ethers arises probably from the fact
that the whole of the hydrogen present is united to carbon.
Note the action of sodium and PCI- on alcohol and on ether.
The ethers are not decomposed with PCI.-, except on heating,
when they give the alkyl chlorides,
(C,II,).,0 -I- PC!r, ~- 2C>II,Q -f- POCL
Hydracids, especially 111, have a similar action— .'
(tyU-P -I- 2111 - 2CjII,,I -I- 1I20.
1 lot, strong sulphuric; acid breaks up ether into ethyl sulphuric
acid and water,
(Coiy-jO |  2ll,S()., ::~ 2CoIIrj.SO4IL -|   ILO.
Compare the action of caustic alkalis on ethers, esters and
/Vis               /C'-jHr,                 ^CO.CIL
O                         O                           O
Vui.-,            ^co.cii..,           N.:o.cir:i
Diclliy! ether.              Kthyl acetate.             Acetic auliytlriclc.
1'RKl 'A RATION     4.
Bthylene Bromide. -The formation of olefmcs by the
action of cone. HoSO., and other dehydrating agents on the
alcohols is a very general reaction.    Among the higher alcohols                 \<
the action of heat alone suffices ; celyl alcohol, C1(il lr;1(), gives                    }
cetylene, C1(I,M;,.>, on heating.    The olefines are also obtained by                   ,J(
the   action   of   alcoholic  potash  on  the   alkyl  bromides  and                    * ,i •
iodides,                                                                                                               • || ,
CJIfiUr -I- K(JH =.- C3ir4 4- KBr -I-11.0,                                          L j
and by the electrolysis of th« dibasic salts ; potassium succinalc                    »
'gives ethylene,                                                                                                \\
CoIUax^KJo = Coll., -I  2CO, + K,(II,).                                         I
The olefines combine with :                                                                               |i
(i)  Hydrogen in presence of platinum black, or finely divided                    111
nickel (see Prep. 78, p. 181).                                                                             I
CII«:CIIS + II,j = CII3.CIIa.                                                  ^
Ethvlewu.                      Ethane.                                                                   ^